The escalating deployment of wireless networking and communications technologies is causing a corresponding increase the number of wireless and portable devices, and applications for those devices. As a result, increasingly more computing resources are integrated into and utilized by portable and wireless applications (“portables”). Markets for portables demand devices with high data throughput rates, for applications such as multimedia and streaming media, voice over data, and others. At the same time, markets for portables also demand devices that are convenient to use—both from a form factor and use-time perspective. Thus, designers and manufacturers are faced with demands for greater versatility and processing power, coupled with demands for smaller devices with longer battery life (i.e., very low power consumption).
Initially, at least, attempts were made to address battery life concerns by improving battery systems—both battery density and charging efficiency. Unfortunately, however, such approaches were only successful for a short time, as the steadily increasing demands on portable performance outpaced the ability to improve battery systems. Designers and manufacturers have realized that the performance demands of new portables cannot be met by simply by increasing energy density in batteries.
To increase the functionality and use time of portables, designers and manufacturers are turning to high efficiency management of system functions. When the amount of energy that is needed to complete a function is decreased, a battery has more energy left to perform other processes. This simple approach to energy management has been applied throughout portable devices and systems.
Consider, for example, that various portable devices and systems (e.g., MP3 players, digital cameras) do not require full operation of all device circuitry all the time. There are certain times when various components or functions are idle and, depending upon the application, may be powered down to reduce overall system power consumption. Unfortunately, however, many digital data processing and transmission applications rely upon clocking signals and systems for recovery from power-down states, as well as for routine operation. As a result, in a number of conventional systems, clocking functions or circuitry cannot be powered down even where its associated operational circuitry is idle. Typically, a clocking element or system has a relatively high switching factor, which results in significant power consumption.
This concern becomes even more important when—as is the case in many modern portable devices and systems—a certain device or component relies upon a serial interface. In systems where clocking is always active, even when data is transmission or communication may be idle, the interface and associated circuitry are also always active and consuming power unnecessarily.
As a result, there is a need for a system that provides a versatile clock management for ultra low power applications—particularly for low power portable systems and devices utilizing serial interfaces; a system that provides clocking functionality only when device operations require it, and otherwise powers down clocking to provide efficient, low-power data processing or communication in an easy, cost-effective manner.